Storage devices including a semiconductor memory and a controller for controlling the semiconductor memory are known. Such a storage device may be manufactured by preparing a manufactured semiconductor memory and assembling it with a controller. It is generally desirable, as regards a method to evaluate manufactured storage devices, to detect not only defects during the evaluation but also suppress defective rates after shipment, because it is desirable to avoid potential defects likely to occur in the devices that have passed a certain evaluation method in the early stage after shipment as much as possible. For this reason, there is a need to detect, during an evaluation, potential defects which have gone undetected during certain other evaluations utilising other evaluation methods but which could become actual defects soon after the shipment.